What to do when Qantas don't see award space seen by other Oneworld airlines?

I’m trying to add a Helsinki to Singapore flight (3 persons) to a round the world booking. I’m seeing seats available on Finnair on December 27 and other dates. I call qantas but they keep denying that the seats are available

I’ve checked on the BA site and with the KVS tool. Both confirmed that the seats are available. What should I do next? Thanks in advance for any advice.

Can you see reward seats on the Qantas website if you look up that segment individually? If not, then perhaps there is an issue with Qantas not having access to that inventory. A similar problem exists with Qatar Airways where Business rewards into/out of Australia are capped at 1 through Qantas, but up to 4 seats available with other programs.

The reward seats are visible on the Qantas website when I look up the segment individually. As noted, I can also see them on KVS & the BA site. Puzzled by the fact that Qantas Customer Service don’t see them, and what I should do next.